Data processor and compactor therefor

ABSTRACT

A data processing system and compaction means therefor sums groups of incoming data signals and provides a composite data signal for each group of signals summed. The composite signals are correlated in a predetermined sequence and provide correlated output signals indicative of the information contained in the plural data signals.

Unite States atom Houser et al.

[451 July 25, 1972 DATA PROCESSOR AND COMPACTOR THEREFOR George G.l-louser, San Diego, Calif.; Robert E. Jenkins, Owego, N.Y,

International Business Machines Corporation, Armonk, N.Y.

April 4, 1969 inventors:

Assignee:

Filed:

Appl. No.:

U.S. Cl ..343/l7.l R, 343/5 CM Int. Cl ..G0ls 7/30 Field of Search...343/5 PD, 17.1 R, 5 CM [56] References Cited UNITED STATES PATENTS3,133,281 5/1964 Young etal ..343/l7.l X 3,333,267 7/1967 Williams....343/l7.l 3,422,432 i/l969 Richmond ..343/l 7.1

Primary Examiner-J. l-l. Tubbesing Attorney-Hamlin and Jancin and NormanR. Bardales [5 7] ABSTRACT A data processing system and compaction meanstherefor sums groups of incoming data signals and provides a compositedata signal for each group of signals summed. The composite signals arecorrelated in a predetermined sequence and provide correlated outputsignals indicative of the information contained in the plural datasignals.

26 Claims, 12 Drawing Figures SINE CHANNEL PATENTEDJULZS I972 3 680., 1O3 sREEI 1 0F 4 n l v PRESUM CORRELATION J L TR cNs TRACKS RAW AZIMUTHl/PRF E RANGE M2 1m COSINE SINE COSINE SINE gg 2 STORAGE AZIMUTH DRUM,DATA COMPACTOR F cRsRERNRARNEL "7 I 2A 1 UTILIZATION I 60 L i Ramada lT 1 PHASE BANDWIDTH R A ,9 l DETECTOR REDUCER PRESUM I DISPLAY I A 1cos. 8Q 40 5A g l g 1 l SlNE/COS. g :41 1 3' REFERENCE 7 w I i 5GENERATOR J g i 3 Q I A i A i 1 A STORAGE A PHASE BANDWIDTH A DETECTORREDUCER PRESUM E i A L SINE CHANNEL 28 1 l INVENTORS GEORGE G. HOUSERROBERT E. JENKINS BYWMM gwaiw" AT TORNE Y Ccos SUMMING AMP T i l MEANSARITHMETIC Csin MULTIPLIER MULTIPLIER MULTIPLIER 410 a f DEMODULATOR ,41READ AMP LIMITER ,41 READ AME,

umnm DEMODULATOR REVOLUTION N0."

REVOLUTION CORRELATOR TRACKS REVOLUTION FBGIM READ AME, LIMITER,&DEMODULATOR sum 2 or 4 wwmm GATE

REVOLUTION REVOLUTION PRFSUM TRACK N05,

WRITE AMP FM MODULATOR Cos.

DATA PROCESSOR AND COMPACTOR TIEREFOR The invention herein described wasmade in the course of or under a contract with the Department ofDefense.

BACKGROUND OFTI-IE INVENTION This invention relates to a data processingsystem and data compaction means therefor, and is particularly usefulfor radar data processing systems.

Data processing and data compaction systems are well known in the art.For example, one such prior art system is described inU. S. Pat. No.3,271,765 entitled Data Compression Processing System, S. R. Pulford,and assigned to the same assignee herein. In that particular patent, thesystem is embodied in a radar data processing system of the side-lookingtype. Briefly, the prior art system contemplates utilizing the radarsignal returns to modulate the beam intensity of an electronic CRTscanner which is adapted to scan an unexposed recording film in a rastertype mode. The start of each scan is synchronized with the interrogatingpulses and as the beam sweeps across the photographic recording mediumit exposes the emulsion in proportion to the modulation produced by thesignal returns. As the successive interrogating signals are transmitted,the resultant successive signal returns coming from the same range arerecorded adjacent to each other in the recording medium. Subsequentlythe roll of film is developed and thereafter when it is desired to readout the azimuth information of the target points in a given range, thedeveloped film transparency is juxtaposed between a flying spot scannerand photomultiplier tube and the beam of the spot scanner is moved alonga line transverse to the direction in which the signal returns wererecorded. The position of the line of course corresponds to the desiredrange of interest. For further information concerning the details andoperations of the aforedescribed prior art system, reference should bemade to the aforementioned patent. While such systems have been foundsatisfactory, their application for processing radar signals on a realtime basis have been limited by the requirement to record each and everyradar signal return and subsequently to readout each and every recordedsignal return. Furthermore, when the film is utilized as the recordingmedium additional time is required to develop the film and the system isthus not amenable to processing the data signals on a real time basis.In considering todays state of the art wherein each and every targetpoint in each and every range may be subjected to multiple hits, e. g.1,500 hits, from successive multiple interrogating pulses, it can bereadily seen that an improved data processing and compaction system isrequired.

SUMMARY OF THE INVENTION It is an object of this invention to provide animproved data processor and/or data compaction system which processesthe information on a substantially real time basis.

It is another object of this invention to provide a data processorand/or data compaction system utilizing magnetic storage means.

It is still another object of this invention to provide a data processorand/or data compaction system utilizing magnetic storage means of thedynamic type and/or particularly of the drum or disk type.

It is still another object of this invention to provide a radar dataprocessor and/or radar data compaction system for processing radarreturn signals on a substantially real time ba- SIS.

Still another object of this invention is to provide a radar dataprocessor and/or radar data compaction system for processing radarreturn signals of a side-looking radar apparatus.

According to one aspect of the invention there is provided a datacompaction system for compacting plural data signals. Each of the datasignals has first and second information characteristics. The compactionsystem has a first means for presumming predetermined groups of the datasignals and providing for each group summed an output first signalhaving characteristics proportional to the aforementioned first andsecond information characteristics of the data signals of the particulargroup. In addition, a second means for correlating the output signals ofthe first means in a predetermined sequence is provided. The secondmeans provides correlated output signals indicative of the informationof the plural data signals.

According to another aspect of the invention there is provided a dataprocessing system which includes the aforementioned data compactionsystem and which further includes a utilization device responsive to thecorrelated output signals of the aforementioned second means.

According to still another aspect of the invention the aforementioneddata processor system and/or data compaction system are preferablyembodied in radar data processing system and/or a radar data compactionsystem.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of the preferred embodiments of the invention as illustratedin the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic view shown inblock form of a preferred embodiment of the invention;

FIG. 2 is a diagrammatic representation of an aircraft in flight withside-looking radar apparatus in operation;

FIG. 3 is a waveform diagram shown in idealized form of an interrogatingsignal pulse emitted by the radar apparatus of FIG. 1 and the resultantecho return signals;

FIG. 4 is a schematic view of the magnetic storage means employed in thesystem of FIG. 1;

FIG. 5 is a schematic view shown in block form of the cosine I presummerof FIG. 1;

FIG. 6 is a schematic view shown in block form of the cosine portion ofthe correlator shown in FIG. 1;

FIGS. 7a-7e are waveform diagrams utilized in the explanation of thepresent invention; and

FIG. 8 is a table helpful in the explanation of an illustrative exampleof a preferred recording operational mode employed by the presentinvention.

In the Figures, like elements are designated with similar referencenumerals.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, datasignals from a signal source 1 are processed by the data compactor 2.The data signals are compacted by compactor 2 and the compacted datasignals in turn are fed to a utilization device 3. Data compactor 2comprises presum means, generally indicated by the reference numeral 4,and correlator means 5. The presum means 4 sums groups of the inputsignals and provides a composite signal for each group. The correlatormeans 5 sequentially correlates the composite signals and providescorrelated output signals indicative of the information contained in thedata signals. Means 4 and 5 coact to compact the data signals of source1 as will become apparent from the detailed discussion hereinafter. Thecorrelated output signals are further processed by the utilizationdevice 3. For example, device 3 may be an indicator or a display system9 and/or a storage system 9'. Preferably, systems 9 and 9' are a CRTdisplay system and a magnetic tape storage system, respectively. Aswitching means 3' provides independent as well as simultaneousoperational modes for systems 9 and 9.

In the preferred embodiment, the data processing system of FIG. 1 isutilized as a radar data processing system for a sidelooking radarsystem. The side-looking radar system is a coherent, pulsed-Dopplerradar which employs a syntheticaperture antenna, such radar systemsbeing well known in the art. Signal source 1 is accordingly an airbornecoherent radar transmitter/receiver apparatus which emits high frequencyinterrogating signal pulses from the synthetic-aperture antenna la andreceives thereat the radar returns or target echos. The

receiver portion of apparatus 1 converts the radar return video signalsto IF signals at its output in a manner well known to those skilled inthe art and the IF signals are fed to the input of the data compactor 2.

For the particular radar system, the video IF signals are preferablyprocessed by the compactor 2 in two quadrature related signal channelsto mitigate the effects of signal clutter. These channels arehereinafter referred to sometimes as the cosine and sine channels 2A,2B, respectively, of compactor 2. Each channel includes one of therespective presummers 4a, 4b, which are part of presum means 4. Itshould be understood that in other types of radar and/or data processingsystems, only one signal channel and consequently only one presummer maybe utilized such as, for example, in radar and/or data systems wheresignal clutter effects are negligible and/or absent. For the particularradar data processor embodiment being described, however, it ispreferred that the IF signals are phase detected in the cosine and sinequadrature channels 2A and 2B by means of the respective phase detectors6a and 6b, respectively. More particularly, the IF signals are phasedetected by detectors 6a and 6b with respect to predetermined relatedcosine and sine reference signals, respectively, provided by the sineand cosine reference signal source or generator 7. Each quadraturesignal component has information and clutter sub-components. When thequadrature signal components of channels 2A, 2B are subsequentlycombined into a resultant signal by the correlator means 5, therespective clutter subcomponents of each effectively cancel each otherout. As contemplated herein the cosine and sine quadrature signalcomponents are generated simultaneously from the returns of the sameinterrogating signal pulse. Alternatively, it should be understood thatthe cosine and sine quadrature signal components may be generatedalternately in a time multiplex fashion from the returns of thesuccessive interrogating pulses. In the latter case a suitable timedelay means would be provided in one of the channels which would bringthe quadrature signal components into the same time phase relationshipwith respect to each other prior to their correlation by the correlatormeans 5.

Moreover, in the particular embodiment being described, the quadraturechannels are also further provided with respective bandwidth reductionamplifiers 8a, 8b as shown in FIG. 1, each of which eliminates the upperand lower sideband components below a desired decibel level, and thusreduces the bandwidth of the signals being processed. It should beunderstood that in some cases where the bandwidth of the signals beingprocessed are already compatible to the bandwidth response of the datacompactor 2, particularly of the presum and correlator means 4, thereof,then the amplifiers 8a, 8b need not be provided. As is obvious to thoseskilled in the art, if time multiplexing is employed the quadraturesignal components may be processed by certain elements which are commonto both channels such as a common phase detector and/or bandwidthreducer.

In order to better appreciate the principles of the present invention,the side-looking radar system and data processor of FIG. 1 will now bedescribed with reference to FIG. 2. As shown therein, an aircraft 10 istraveling at an assumed predetermined constant velocity along asubstantially straight line path 11 relative to a ground track in thedirection indicated by the arrow. This path coincides for presentpurposes with what is termed the flight reference vector. The aircraftis equipped with the radar apparatus and data processing system 1-3 ofFIG. 1. Accordingly, the onboard transmitter, not shown, of source 1emits at the antenna 1a successive interrogating pulses ofelectromagnetic energy at a fixed PRF. The electromagnetic energy isbeamed toward the terrain at an angle of substantially 90 to the flightvector of the aircraft 10. For sake of clarity, only three radiationpatterns or energy lobes 12 associated with three particular transmittedpulses are shown in FIG. 2, e. g. the lobes designated by the referencecharacters I, II, and III. The lobes or beams 12 are illustrated instylized form and are generally tear-shaped with increasingtransectional dimensions being encountered at greater distances, i.e.ranges, from the aircraft 10. It should also be understood that thespacing l/PRF between successive beams is illustrated with anexaggerated or enlarged scale in FIG. 2 for sake of clarity.

Each target point is subjected to a number of multiple hits fromsuccessive interrogating beams as the craft 10 moves past the particularpoint. By way of example, the target point 13 located at the relativelyremote range R2 is first hit by beam I when the aircraft 10 is at theazimuth location SI. The target point 13 continues to be hit by eachsuccessive interrogating beam transmitted during the time period TA.With the aircraft in the azimuth position SII, as shown in FIG. 2, thebeam II is directly abeam of the target point 13, i.e. beam II is atwith respect to the target point 13. When the craft 10 reaches theazimuth position SIII, the beam Ill makes the last hit on target 13.

For sake of comparison, a target point 14 is illustrated in FIG. 2 asbeing at the same azimuth location SIl as target point 13 but at arelatively shorter or closer range R1. Target point 14 is hit bysuccessive interrogating beams transmitted during the time period TB.Due to the aforementioned tear-shaped form of the beams, the number ofhits associated with target point 14 is less than that associated withtarget point 13. Nevertheless, the number of hits in either case issubstantially high. For a particular example of radar system of the typebeing described and a given range, the number exceeds well over 1500hits. Each time a target point is hit, an echo or return signal isreflected back to the apparatus 1, FIG. 1, and is received by theantenna 1a and receiver portion thereof. The pulse repetition frequencyPRF is judiciously selected so that the return signals resulting from agiven interrogating beam are received prior to the transmission of thenext succeeding interrogating beam in a manner well known to thoseskilled in the art. Also, as is well known to those skilled in the art,the return times of the respective return signals associated with anygiven interrogating beam is proportional to the respective rangeinformation associated with'the target points producing the returnsignals. Thus, for example, as shown by the idealized waveforms of FIG.3 for the particular interrogating energy lobe or pulse II, itsassociated return signals will include a return signal E1 first from thecloser target point 14 and then a return signal E2 from the furthertarget point 13, the respective times t1, t2 of return of each of theselastmentioned return signals being proportional to the ranges R1 and R2,respectively.

Moreover, during successive radar contacts with a target point, asdescribed above, a Doppler effect is produced in the successive returnsignals associated with the particular point due to the change inrelative velocity between the target point and the craft 10 duringsuccessive interrogations. The Doppler effect is characterized by theenvelope produced by these signals and is utilized to ascertain theazimuth information associated with the target point. Without thepresent invention the processing of the return signals associated witheach of the multiple hits associated with each target point for eachrange and for each azimuth location would require a complex and vastamount of information channels and data processing equipment. The dataprocessing system of the present invention, however, simplifies andreduces the amount of information channels and data processing equipmentrequired to process the return signals.

In the preferred embodiment both the presum means 4 and the correlatormeans 5 utilize magnetic storage means and preferably storage means ofthe drum or disk type such as, for example, the common drum 15illustrated in FIG. 4. The drum 15 has a finite number of plural tracks15-1 to 15-N. Tracks 15-1 to l5-n are assigned to the presum means 4 andtracks 15-n+1 to 15-N are assigned to the correlator means 5. Access tothe tracks of the drum 15 is provided by the aligned READ/WRITE heads16, each of which is associated with one of the tracks 15-1 to 15-N.One-half of the allocated presum tracks 15-1 to l5-n are furtherassigned to the presummer 4a of the cosine channel 2A and the other halfare assigned to the presummer 4b of the sine channel 28. Similarly,one-half of the correlation tracks l5-n+1 to l5-N are allocated to theportion of the correlator means 5 associated with cosine channel 2A andthe other half are allocated to the portion of the correlator means 5associated with the sine channel 2B. The rotation of the drum issynchronized with the PRF of the aforementioned interrogating signals.By way of example, the drum is assumed to make one complete revolutionper interrogating signal. Consequently, only a single row of READ/WRITEheads 16 are required for the given example. Each revolution commencesfrom a reference position corresponding, for example, to the closestrange R for which the radar system is capable of receiving returnsignals. Thus, for each revolution as the drum rotates in the directionindicated by the arrow A, the return signals associated with aparticular interrogating signal, after being phase detected andbandwidth reduced, are recorded via the appropriate READ/WRITE head 16on one of the cosine and one of the sine presum tracks. For theillustrated counterclockwise direction A, the echo returns, i.e. signalreturns, are recorded from the closest range R0 to the remotest range onthe particular track in a clockwise direction as indicated by thedirection arrow marked RANGE. As the signal returns from successiveinterrogating pulses are written on successive tracks, the rangeinformation associated with corresponding range bins, e.g. the range bindesignated R1 in FIG. 2, are recorded in corresponding radial positionsof the presum tracks. Thus, in the preferred embodiment successivereturn signals from the same range which are derived from successiveinterrogating pulses when recorded on the successive tracks arespatially aligned with respect to each other.

In the presum means 4, a plural number of serial, i.e. sequential, WRITEoperations are performed and these are followed by a single parallelREAD operation. In the preferred embodiment, the serial WRITE operationsare performed on a preselected number of successive presum tracks whichis less than the number of assigned presum tracks. After the informationhas been recorded on a first group of successive presum tracks of thepreselected number, the parallel READ operation is performed on thisgroup of presum tracks while a WRITE operation is being performed on thenext presum track. Also, the addressing system for the presum tracks isarranged such that as information is being written into one of thetracks the next succeeding track is being erased. After the parallelREAD operation is performed, as the tracks of the particular group readout are sequentially erased they become available for recording theinformation after the last track of the assigned presum tracks isutilized. Each time information has been recorded on a group ofsuccessive presum tracks of the preselected number, the parallel READoperation is performed simultaneously while WRITE and ERASE operationsare being performed on the next two succeeding presum tracks,respectively. The case of the aforedescribed recording technique willbecome apparent from the description hereinafter with reference to FIGS.and 8.

Alternatively, because of the high sampling rate or PRF employed, theserial WRITE operations may be performed until all of the assignedpresum tracks are utilized before the parallel READ operation isperformed. In such a case, the amount of information not recorded duringthe readout operation is negligible. However, in still another casewhere it is desired to record all the return signals, the presum tracksmay be further assigned into two or more sets of successive tracks sothat while a READ operation is being performed in one of the sets, theserial WRITE operation continues in the tracks of the next set. In thislatter case, in the preferred embodiment the sine signals recorded onthe successive presum tracks being read out. It should be understoodthat in the preferred embodiment the two quadrature components of aninput signal which are fed to the presummers 4a and 4b, respectively,are simultaneously written into respective single sine and single cosinepresum tracks thereof. Thus, in the preferred embodiment each outputsignal of the presum means 4 also has two components which are derivedfrom the particular plural cosine and plural sine presum tracks,respectively, being read out. The output signals of the presum means 4are sometimes referred to hereinafter as composite signals. Theforegoing will become more apparent with reference to the detaileddescription hereinafter of the presummer 4a illustrated in FIG.

Each composite signal, or in the case of the preferred embodiment, eachquadrature component of the composite signal, in turn, is recorded on anexclusive correlator track of the drum 15. Moreover, the compositesignals are synchronously recorded on successive correlator tracks suchthat the range information associated with the same range bin andcontained in the successive composite signals are recorded in the samecorresponding radial positions of the correlator tracks. In thepreferred embodiment, the range bins of the correlator tracks arealigned with the corresponding range bins of the presummer tracks, c.f.range bin R1 illustrated in FIG. 4. The correlator employs a serialWRITE operation when recording on the correlator tracks. In thepreferred embodiment, the two quadrature components of a compositesignal are simultaneously written into single sine and single cosinecorrelation tracks, respectively. After each WRITE operation a parallelREAD operation is performed on all the correlation tracks. Sometimeprior to the next WRITE operation, an erase operation is performed onthe next sine and cosine correlation tracks of the sequence which willrecord the next incoming composite signal. Thus, in the preferredembodiment, the oldest information contained in the sine and cosinequadrature correlation tracks is being continuously removed and updatedwith the information of the newest or latest incoming composite signal.During the READ operation associated with the correlation tracks, theindividual recorded composite signals being read out are weighted with areference function from which the information relative to the azimuthcharacteristic is resolved. The weights assigned to the individualreference signals are continuously being shifted in a manner hereinafterdescribed in greater detail with reference to the description of thecorrelator illustrated in FIG. 6 and the illustrative operationalexample shown in the table of FIG. 8.

Referring now to FIG. 5, there is shown a preferred embodiment of thepresummer 4a of FIG. 1. It should be understood that the presummers 4aand 4b are identically configured and thus only presummer 4a is shown inFIG. 5 for sake of clarity. Presum means 4 reduces the sampling rate ofinformation to the correlator means 5 with respect to the rate ofinformation being provided by the signal source 1. More particularly, inthe preferred radar system embodiment, the sampling rate of the radardata going to the correlator means 5 is reduced with respect to the PRFrate that the basic radar samples the terrain. As shown in FIG. 5 the IFinput signals from the receiver portion of the radar apparatus, i.e.signal source 1 of FIG. 1, after being phase detected and bandwidthreduced by the circuits 6a, 8a, respectively, of channel 2A, are fed tothe input 17 of FM modulator 18 of presummer 4a. The signals at input 17frequency modulate a carrier signal that is to be recorded on the cosinepresum tracks 15-1 to l5-m of drum 15, FIG. 4. In the drawing, referencenumerals 15-1 to l5-m are used to designate the cosine presum tracks andcorrespond to one-half of the tracks 15-1 to IS-n illustrated in FIG. 4.It should be understood that the sine presum tracks, not shown, aredesignated by the reference numerals 15-m+l to 15-n and are included inthe presummer 4b. The modulated carrier signal is fed to the odd andeven write amplifiers 19, 20 via respective gates 21, 22. Moreparticularly, the modulated carrier signal of modulator 18 conditionsone of the respective two inputs of each of the gates 21, 22. The otherinputs of the respective gates 21 and 22 are coupled to the 1 andoutputs of a bi-stable multivibrator 23 which is driven by asynchronization pulse signal S applied to terminal 24. Synchronizationsignal S is derived from the interrogating signal of signal source 1 bysuitable means, not shown, and has a prf equal to the basic radar PRF.In response to the pulses of the synchronization signal S applied to thecomplementary input C of multivibrator 23, the odd and even gates 21 and22 are alternately actuated. The output 19a of the odd write amplifier19 is connected to the data inputs I of each of those gates 25designated by the legend ODD GATE in FIG. 5. The outputs of ODD GATES25, in turn, are connected to the respective write windings 16a of theREAD/WRITE heads 16 associated with the respective odd track's -1, 15-3,15-5 15-m-1, it being assumed for sake of explanation that m is an eveninteger. Similarly, the output a of the even write amplifier 20 isconnected to the data inputs I of each of the EVEN GATES whose outputsare connected in turn to the respective heads 16 associated with theeven tracks, e.g. tracks 15-2, 15-4 15-m. Each gate 25 also has twoother control inputs, to wit: a write input W and an erase input E. An mstage ring counter 26, where m is greater than one and as aforementionedis assumed to be an even integer, controls the gates 25.

Each read windings 16b of the respective heads 16, FIG. 5, is connectedto the input of a mutually exclusive one of the read amplifiers 27. Theoutput of each read amplifier 27 is coupled to one of the limiter anddemodulator cascaded stages 29, which are illustrated schematically by asingle block for sake of simplicity, via an inhibit gate 30. The limiterportion of each block 29 amplitude limits the signals from itsrespectively associated amplifier 27 and the demodulator portiondemodulates the frequency modulated signal being read out by itsassociated amplifier 27. Actuation of gates 30 are controlled by thering counter 26.

In the preferred embodiment a weighting operation is performed in thepresum means 4. Thus as the signals are read out from the groups of thetracks 15-1 to IS-m, they are amplitude weighted with respect to areference function in the respective weighting amplifiers or attenuators28 which are coupled to the output of the limiter/demodulator stages 29.The gain of the attenuators 28 are digitally controlled by the outputsignals of the two in stage shift registers 31 and 32. The weightingoperation provided in the presum means 4 shapes the output signals beingread out to a desired filter shape characteristic, eg a Gaussiandistribution. The digital control signals generated at the outputs a1,a2, am and b1, b2, bm of registers 31 and 32, respectively, thus changethe respective gains of the attenuators 28 so that each signal beingread out is modified by a particular one of the weighting componentswhich are the inverse Fourier transforms of the desired filter shapecharacteristic. Shift registers 31 and 32 are advanced by thesynchronization signal S which, as aforementioned, has a prf equal tothe basic PRF of the interrogating radar signals of the signal source 1.

Each of the respective outputs of the attenuators 28 is coupled to oneof the multi-inputs of summing amplifier 34 which sums the weightedsignals. An output of the summing amplifier 34 is coupled to the inputof gate 35. Gate 35 is actuated by the control signal S generated bygate control circuit 36. Control circuit 36, which may include a counterfor this purpose, provides in the preferred operational mode an outputpulse signal S every m-2 pulse of signal S applied to its input. As aconsequence, each time gate 35 is actuated, an output signal Ecos isprovided at the output of gate 35 that is indicative of the informationcontained in the particular group of tracks 15- 1 to 15-m being read outin the presummer 4a. The signal Ecos and the signal S are fed to thecosine portion of the correlator means 5 shown in FIG. 6 via conductors35' and 24', respectively. In a similar manner, presummer 4b provides asignal Esine to the sine portion of the correlator means 5. Signal S isutilized to drive the counter and shift register counterparts ofpresummer 4b corresponding to the counter 26 and registers 31, 32 ofpresummer 4a.

Ring counter 26, as aforementioned, controls the operations of gates 25and 30. In the preferred mode of operation as the counter 26 is advancedby signal S, the signals at the outputs K1, K2, Km sequentially open thegates 25 associated with tracks 15-1, 15-2, 15-m, respectively, byvirtue of their respective connections to the write inputs W of thegates 25. In this manner the alternate FM signals at the outputs ofamplifiers 19 and 20 are written on the tracks 15-1, 15-2, 15-m insuccession, a track being written into each time the gate 25 associatedwith the particular track is opened. Moreover, the outputs K1, K2, Kmare also connected to the erase input E of the gates 25 associated withtracks 15-2, 15-3, 15-m, 15-1, respectively. Consequently, as the ringcounter 26 advances, it erases the information recorded on the tracksucceeding the one being written into. In addition, the outputs K1, K2,Kn are connected to one of the control inputs of the inhibit gates 30associated with the tracks 15-1, 15-2, l5-m, respectively, as well asthe other control inputs of the gates 30 associated with the tracks15-2, 15-3, l5-m, 15-1, respectively. Consequently, when the WRITE andERASE operations are being simultaneously performed on two adjacenttracks, the gates 30 associated with these two particular tracks areinhibited. As a result, no output signal is available for readout fromthe tracks whose gates are so inhibited and hence cannot interfere withthe READ operation being performed on the other tracks, which readoutoperation is controlled by the coaction of the gate 35 and controlcircuit 36 in response to the signal S as previously explained.

Referring now to FIG. 6 there is partially shown a preferred embodimentof the correlator means 5 of FIG. 1. It should be understood that onlythe portion of the correlator means 5 associated with the cosinequadrature channel 2A is illustrated in FIG. 6. The portion of thecorrelator means 5 associated with the sine quadrature channel 28 isidentical thereto and hence has been omitted for sake of simplicity.Accordingly, in FIG. 6, each of the presummed signals Ecos are fed viaconductor 35' to the input of FM modulator 37. The signals Ecosfrequency modulate a carrier signal that is to be recorded on the cosinecorrelator tracks of drum 15. In the drawing, reference numerals 15-n+1to 15-n+p are used to designate the cosine correlator tracks andcorrespond to one-half of the tracks 15-n+1 to 15-N illustrated in FIG.4. It should be understood that the sine correlator tracks, not shown,are designated by the reference numerals 15-n+p+l to 15-N and areincluded in the portion of the correlator means 5 associated with thesine quadrature channel 28. It should also be understood that there areequal numbers of cosine and sine correlation tracks.

The modulated carrier signal is fed to the write amplifier 38, theoutput of which is connected to the respective data inputs I of gates39. Each write input W of gates 39 is actuated by one of the outputsignals present at the outputs 1W, 2W,...PW of the p stage write-selectring counter 40 which sequentially addresses the drum tracks 15-n+1 toIS-n-l-p. Each output of a gate 39 is connected to the write winding 16aof a mutually exclusive one of the READ/WRITE heads 16 that areassociated with tracks 15-n+l to 15-n+p.

Each read winding 16b is connected to cascaded read amplifier, limiter,and demodulator stages 41 shown as a single block for sake ofsimplicity. The read and limiting amplifiers remove all amplitudevariations from the recorded frequency modulated signals of the tracksbeing read. The demodulators demodulate the frequency modulated signalsbeing read. The p outputs 41a of the demodulators of stages 41 provide panalog signals.

The p analog signals, as aforementioned, are in turn weighted withanother reference function. The reference function is indicative of theexpected target history that is characteristic for the radar systembeing employed. The weighting operation is provided by the multipliers42 which are preferably dual channel amplifiers. For this purpose, eachmultiplier 42 is connected to the output 41a of one of the readamplifier/limiter/demodulator stages 41. The gain of the multipliers 42are digitally controllable by a pair of p stage shift registers 43a and43b which provide the amplitude and sign characteristics, respectively,of the reference function. The weighted signals at the multiplieroutputs 42a are then summed in a summing amplifier 44 which providescorrelated output signal components Ccos. The sine portion of thecorrelator means simultaneously provides a correlated output signalcomponent Csine. The signals Ccos and Csine are combined by suitablearithmetic circuit means 45 which provides a resultant signal Erinresponse thereto. Output gate 46 periodically gates the output signal Erto the output 47 which as shown in FIG. 1 is connected to the input ofutilization device 3.

Gate 46 is controlled by the read stage R of a shift register 48. Thefirst stage W of register 48 also advances the writeselect register 40and its last stage E advances the erase-select register 49 whose outputs1E, 2E, PE are connected to the respective erase inputs E of the gates39 associated with tracks l5-n+l to l5-n+p, respectively. Register 48 isadvanced by the signal S present at the conductor 24 which is connectedto its input. It should be understood that the arithmetic circuit means45, gate 46, and register 48 are common to both the sine and cosineportions of the correlator means 5 of FIG. 1.

Shift register 48 provides an output signal at one of its outputs eachtime the register 48 is advanced by a pulse of the input signal S.Consequently, the register 48 first operates the write-select register40, next operates the read output gate 46, and next the erase-selectregister 49, whereupon the cycle is repeated. Moreover, the WRITE, READand ERASE operations are thus performed in mutually exclusive timeperiods in the preferred operational mode of the correlator means 5. Asaforementioned, during the READ operation registers 43a and 43b aresimultaneously operated by virtue of their respective inputs beingconnected to the output of stage R of register 48.

The first output signal appearing at the output of stage W of register48, it is assumed by way of example, causes the first stage of register40 to provide an output signal at its output 1W which opens the gate 39associated with track -n+l. As a consequence, the FM signal present atthe output of amplifier 38 is written on track l5-n+l. In the givenexample, when the next pulse of signal S advances the register 48, thereappears at the output of stage R a signal which opens gate 46 and allowsthe output signal Er to be read out of the correlator means 5 of FIG. 1.During a READ operation all of the correlator tracks in the preferredoperational mode are read out in parallel in the correlator means 5.When the next pulse of signal S advances the register 48 it provides anoutput signal at its stage E which advances the erase-select register 49and causes the latter to provide an output signal at one of its stageswhich erases the next correlator track into which the next FM signal isto be written. For the given example, this would be track l5n+2 andconsequently the register 49 would provide an output signal at itsoutput 2E which is connected to the gate 39 associated with thatparticular track.

When the next pulse of signal S is applied in the given example to theregister 48 it returns to its first stage W causing the write-selectregister 40 to advance and an output signal to be present at the outputof its second stage 2W. Consequently, the output signal at output 2Wopens the gate 39 associated with track 15-n+2 and the FM signal fromamplifier 38 is written into track l5-n+2. Thereafter there follows theparallel readout operation followed by an ERASE operation of theinformation on the next track, i.e. track l5-n+3. After a WRITEoperation has been performed on the last track 15-n+p and followed bythe parallel readout operation, an ERASE operation is performed on thefirst track 15-n+l and the aforedescribed WRITE/READ/ERASE cycle isrepeated. In this manner, the oldest information is being continuallyupdated.

Referring now to FIGS. 741-72, 8 an example illustrating the principlesof the preferred operational mode of the presummer and correlator means4, 5 will now be described. It is assumed in the given example for sakeof clarity that only a single channel is utilized in the data compactor2 and that the number of presum tracks is five and are designated in thetable of FIG. 8 as tracks Tl-TS. Furthermore, it is also assumed thatthe number of correlator tracks is three and are designated in the tableof FIG. 8 as tracks TA-TC. Thus, for the given example, N=8, n=m=5, andp=P=3. Accordingly, tracks Til-T5 correspond to the tracks 15-1, 15-2,15-3, l5-m-l, and 15-m, respectively, of FIG. 5 and the tracks TA-TCcorrespond to tracks l5-n+ll, 1-n+2, and l5-n+p of FIG. 6.

Moreover, in the given example the first and second coefficientweighting registers 31 and 32, respectively, of FIG. 5 have five stageseach corresponding to the assumed number of presum tracks. The outputsof the five stages of register 31 are designated in the table by thereference characters a1, a2, a3, a4 and a5 and the outputs of the fivestages of registers 32 are designated therein by the referencecharacters bl, b2, b3, b4 and b5. Outputs al-aS of the table correspondto the outputs a1, a2, a3, not shown, am-l and am, respectively, ofregister 31 of FIG. 5. The outputs of bl-bS of the table correspond tothe outputs bl, b2, b3, not shown, bm-l and bm, respectively, of theregister 32 of FIG. 5. In a similar manner, the amplitude and signregisters 43a and 43b each have three stages corresponding to the numberof assumed correlator tracks of the given example. The outputs of thethree stages of the amplitude register 43a are designated in the tableof FIG. 8 as 1A, 2A and 3A and correspond to the outputs 1A, 2A=PA1, andPA, respectively, of the register 43a of FIG. 6. Likewise, the outputsof the three stages of the sign register 43b are designated in the tableas 18, 2S and 3S and correspond to the outputs IS, 2S=PS-l, and PS,respectively, of register 43b of FIG. 6.

Also, for the given assumed example, the ring counter 26 of FIG. 5 hasfive stages with output designations Kl-KS in the example correspondingto the designations K1, K2, K3, not shown, KM-l and KM of the ringcounter 26 of FIG. 5. Similarly, each of the shift registers 40 and 49would have three stages. In the given example, the outputs of register40 are designated as 1W, 2W and 3W and correspond to the outputs ofregister 40 designated 1W, 2W=PW1, and PW, respectively, of the register40 of FIG. 6. Likewise, in the given example the outputs of the register49 are designated 1E, 2E and 3E and correspond to the outputs 1E,2E=PE1, and PE, respectively, of the register 49 of FIG. 6.

Prior to the recording of the data on the drum 15 of FIG. 4 it isassumed that the tracks thereof do not contain any recorded data. At thestart of the first revolution which is synchronized with the firsttransmitted interrogating pulse, the resultant signal S causes a controlsignal to be present at the output K1 of counter 26. This control signalin turn is fed to the write input W of the gate 25 associated with thefirst track T1, i.e. track 15-1, thereby opening the particular gate 25.Accordingly, during the first drum revolution designated No. l in thetable of FIG. 8, the data D10 derived from the returns of the firstinterrogating signal of the radar apparatus of signal source 1 iswritten into the first presum track T1. In the table the operationsuffixes W, E and R indicate, respectively, WRITE, ERASE and READoperations.

Simultaneously, during the first operation, an ERASE operation E isperformed on the presum track T2 as a result of the control signal atoutput Kl being fed to the erase input E of the gate 39 associated withtrack T2. A parallel readout operation is also simultaneously performedon the remaining tracks T3, T4 and T5 due to the absence of any controlsignals to the gates 30 associated with the tracks T3, T4 and T5.However, the control signal at output Kl inhibits the gates 30associated with tracks T1 and T2 for the reasons previously explained.Moreover, the gate 35 is opened by the control signal S of controlcircuit 36 in response to the signal S derived from the firstinterrogating radar signal and the information recorded on the tracksTil-T5 being read out and summed in the amplifier 34 is present at theoutput 35 of gate 35 during the first revolution. However, since thereis no information in the tracks T3-T5 as well as track T2, the datainformation prefixes have been omitted in the table of FIG. 8 duringrevolution No. 1 for sake of clarity.

During the first revolution a WRITE operation W is simultaneouslyperformed in the correlator track TC which would be the composite signalderived from the information, if present, on the tracks T3, T4, T5, asweighted by the weighting coefficients derived from the coaction of thegain control signals present at the outputs a3, a4 and a5, and b3, b4and b5 to the respective attenuators 28 associated with tracks T3, T4and T5. However, since under the assumed conditions that there is noinformation during the first revolution in tracks T3, T4 and T5, as wellas the correlator tracks TA and TB, the data information prefixesassociated with tracks TA-TC have been omitted in the table of FIG. 8for sake of clarity.

For purposes that will become apparent from the discussion hereinafterthe binary bits at the outputs a1-a5 are set at the beginning of thefirst revolution in the sequence 0, 0, 0, 1, 0, respectively; and thebinary bits at the outputs bl-b5 are set at the beginning of the firstrevolution in the sequence 0, 0, 1, 0, 1, respectively. Also prior tothe first revolution the binary bits at the outputs 18, 28, 3S and theoutputs IA, 2A, 3A are each in the sequence 1, 0, 0, respectively.Likewise, the register 48 is set at the beginning of the firstrevolution in response to the first signal S to provide an output signalat its first stage W which in turn causes the shift register 40 togenerate a control signal at the output 3W of its last stage therebyopening gate 39 associated with the track TC and providing theaforementioned WRITE operation thereof. During the first revolution, thebinary bit present at the output 3E of the last stage of register 49 isin an up or I state. It should be understood that for each of theregisters 40, 48, 49 and the ring counter 26, only one of the outputs isin a binary 1 level and the remainder are at the binary level at anygiven instant of time as is obvious to those skilled in the art. Eachtime the binary counter 26 and registers 40, 48, 49 are incremented theoutput of the next succeeding stage is incremented to a 1 level and thebinary level of the preceding stage goes from its previous up or I levelto a 0 or down level. Whenever an output stage of the counter 26 orregister 40, 48, 49 goes from a binary 0 to a binary 1 level it providesthe aforementioned control signal at the output of the particular stage.

During the next drum revolution No. 2 the information D10 remains on therecorded track T1. Simultaneously, a WRITE operation is performed ontrack T2 and the data D20 is written into the track T2 while an ERASEoperation is being performed on track T3 due to the incrementing ofcounter 26 in response to the signal S derived from the second radarinterrogating signal. Shift register 48 is also advanced by the signal Sduring the second revolution causing a parallel readout operation R tobe simultaneously performed on the correlator tracks TA, TB, TC due tothe binary 1 bit previously present at the output of the first stage Wof register 48 being advanced or shifted to the output of the secondstage R. Again, since there is no information contained in the tracksT3-T5 and TA-TC during revolution No. 2, the corresponding datainformation prefixes have been omitted for sake of clarity in the tableof FIG. 8. The same signal S which provides the lastmentioned outputsignal at output stage R of register 48 also advances the information inthe registers 31 and 32 thus placing respective binary 1 bits at outputsaand bl and b4. The controlsignal at the output stage R also advancesthe registers 43a, 43b thus placing the respective binary 1 bits at theoutputs 2A and 2S, respectively.

During revolution No. 3 data information D and D remain on tracks T1 andT2, respectively, while new data D30 is written into trackj T3 and anERASE operation E is performed on track T4. Register 48 is againadvanced and a control output signal appears at its last stage E. Thecontrol signal at the output of stage E advances register 49 causing thebinary 1 bit previously present at the last output 3E to shift to thefirst output 1E of register 49. Likewise, the respective binary bitspreviously present at the outputs a5 and b1 and b4 are shifted to theoutputs al, 122, and b5, respectively. Gate 46 remains closed andregisters 43a and 43b are not advanced due to the absence of a controlsignal at the output of stage R of register 48.

During the fourth revolution No. 4, the gates 30 associated with tracksT4 and T5 are inhibited by the control signal now present at the outputK4 of ring counter 26. Simultaneously, the control circuit 36 generatesa signal S in response to the fourth signal S derived from the fourthinterrogating radar signal. The signal S opens gate 35 and a parallelREAD operation of the information contained in the tracks Tl-T3 isperformed. The information on the tracks Tl-T3 after being weighted intheir respective associated attenuators 28 are summed in the summingamplifier 34 and are fed to the input of the FM modulator 37 of thecorrelator means 5. Simultaneously, WRITE and ERASE operations are beingperformed on tracks T4 and T5, respectively. The summed information fromtracks Tl-T3, after modulating the frequency carrier of modulator 37,are written on the first correlator track TA, the shift register 48having been advanced to its first stage W and in turn causing the binary1 bit at the output 3W of register 40 to shift to the output 1W. Thecontrol signal at output 1W in turn opens the gate 39 associated withtrack TA allowing the data information associated with the FM compositesignal to be written on the track TA, as aforementioned. Again, itshould be noted that during revolution No. 4 the registers 31 and 32have been shifted and as a result the information in the tracks T1-T3are weighted in accordance with the gain control signal contained inthese registers at outputs a1, a2, a3 and b1, b2, b3. Again the gate 46remains opened and registers 43a and 43b are not shifted due to theabsence of the control signal at the stage R of register 48.

At the next revolution No. 5, the data D20, D30 and D40 remain on tracksT2-T4 and new data D50 is written into track T5 while the old data D10is being erased from track T1. A simultaneous readout operation isperformed on the correlator tracks TA, TB, TC which is correlated inaccordance with the sign and amplitude bits of the now shifted registers43a, 43b. As the drum continues to revolve, the presum tracks are readout in sequential groups. Thus, as shown in the table of FIG. 8, thetracks T1, T2, T3 are read out during revolution No. 4, tracks T4-T5 andT1 are read out during revolution No. 7, tracks T2, T3, T4 are read outduring revolution No. 10, etc. On the other hand, each time a group ofpresum tracks is read out, on the next revolution all the correlatortracks are read out. Thus, tracks TA-TC are read out during revolutionNo. 8, No. l 1, No. 14, etc. It should be noted that at revolution No.10 the correlator tracks TA-TC are filled with data A10, B10, C10,respectively. Data A10 is derived from the data D10, D20, D30; data B10is derived from the data D40, D50, D11; and data C10 is derived fromdata D21, D31, D41. At revolution No. 14 which corresponds to the nextparallel readout operation of the correlator tracks TA-TC theinformation B10 and C10 are still present on tracks TB and TC but,however, new data All is now present on the track TA. Data All isderived from the data D51, D12, D22. Thus, as is shown by the table ofFIG. 8, the presum and correlator track coact to compact the datainformation contained in the input signals from signal source 1.

In order to understand the weighting function provided by the presummermeans 4, reference is made to the waveforms of FIGS. 7a and 7b. In therespective FIGS. 7a and 7b the dash dot waveforms represent by way ofexample the signal envelopes of the information recorded for a givenrange position on the tracks T1, T2, T3 during revolution No. 4 and onthe tracks T4, T5 and T1 during revolution No. 7 referred to in thetable of FIG. 8. The weighting function is shown in solid line form inFIGS. 7a, 7b. By way of example, in the table of FIG. 8 a binary 1binary 0 bits present in the corresponding a and b output stages ofregisters 31 and 32, respectively, that is the corresponding stageswhich feed the same attenuator 28, causes the gain of the particularattenuator to provide a weighting operation at the horizontal upperlevel of the weighting function. However, binary O and 1 bits in thecorresponding a and b outputs, respectively, cause the weightingfunction to be in its intermediate level, and binary bits in both a andb outputs cause the weighting function to be in its lower level, each ofwhich cause corresponding reduction of the gain of the attenuator. InFIG. 7a, after the dash clot signal waveform is attenuated by theattenuators 28 associated with tracks T1, T2, T3, it produces aresultant output signal which when written on the tracks TA has anenvelope characteristic shown by the short dash waveform designated A10therein. During the next readout operation which takes place duringrevolution No. 7, tracks T4, T and T1 are read out and the weightingreference function is shown symmetrically distributed across the tracksT4, T5 and T1. Signal B is the resultant signal derived from theattenuated signal envelope representing the data D40 and D50 and D11 ontracks T4, T5 and T1, respectively, during revolution No. 7. Thus, theweighting function provided in the presummer tracks focuses the combinedsignal returns for the groups of tracks being read out in theaforementioned composite signal and is related to the azimuthcharacteristic of the target point which generates the signal returns onthe particular group of presum tracks being read out.

In FIGS. 7c-7e the dash line waveforms represent the signal envelope ofthe signals present on the tracks TA, TB, TC for the same range but insuccessive readout operations associated with drum revolutions Nos. 1 l,14 and I7, respectively. As shown in FIGS. 7c-7e, when the signal of thetracks TA, TB, TC are correlated with the reference function representedby the solid line step waveform, the resulting signal, e.g. signalsXlg-X3g, further focuses, that is identifies, the azimuth characteristicof the return signals from which the data being read out on the tracksTA, TB, TC are derived. By way of example, in the table of FIG. 8, 1bits in the outputs of corresponding stages of registers 43a, 4317provide the upper and positive level, e.g. the +1.0 relative level ofthe reference function shown in FIGS. 7c-7e; whereas, 0 bits in thecorresponding stages outputs provide the lower and negative level, e.g.the -0.5 relative level of the reference function shown in FIGS. 7c-7e.

The range information characteristic associated with the signalsrecorded on the presum and correlator tracks is derived from the a'priori knowledge of the time of transmission of the interrogatingsignals and the resultant return signals thereof.

ltshould be understood that while the invention has been described inparticular preferred embodiments and a preferred operational mode, thatthe invention could be practiced with other modifications and/oroperational modes. For example, while the invention has been describedutilizing a common storage means, e.g. drum 15, for both the presum andcorrelation information, separate storage means may be employed forstoring the presum and correlation data. Moreover, the invention hasbeen described utilizing one recording track per interrogating signalbut, as is obvious to those skilled in the art, the tracks may besectorized so that the returns from successive interrogating signals maybe recorded in separate sectors of the same track in which case theread/write and erase apparatus would be modified accordingly, such asfor example, for providing plural rows of aligned read/write heads foreach track sector in a manner well known to those skilled in the art.Moreover, it should be understood that while the invention has beendescribed using a simple number of presum and correlation tracks forpurposes of explanation the more presum and correlation tracks and/orsectors utilized to practice the invention enhances the data compactioncapabilities.

Furthermore, the invention has been described in an operational modethat reads out only new information on the presum tracks each time aread out operation is performed thereon. If desired, as is apparent tothose skilled in the art, an operational mode employing overlappingreadout techniques may also be utilized by appropriate modification.

Thus, while the invention has been particularly shown and described withreference to the preferred embodiments, it will be understood by thoseskilled in the art that the foregoing and other changes in form anddetail may be made therein without departing from the spirit and scopeof the invention.

We claim:

1. A data compaction system for compacting sequential input data signalsbeing applied thereto at a predetermined input rate, said systemcomprising:

presumming means having first output means, said presumming meansincluding first storage means and first write apparatus means forstoring said input data signals in successive first groups in said firststorage means, each of said first groups containing a plural firstnumber of successive data signals, first readout apparatus means forsuccessively reading out in a parallel mode each first group of storedsignals, and

first summing means for summing the stored data signals of each firstgroup read out from said first storage means to provide at said firstoutput means a first output signal proportional in a predeterminedmanner to the data signals of the particular first group being summed,said first output signals of said first summing means being sequentiallyprovided thereby at a first output rate less than said input rate;

correlator means having second output means, said correlator meansincluding second storage means and second write apparatus means forstoring said first output signals in successive second groups in saidsecond storage means, each of said second groups containing a pluralsecond number of successive first output signals, second readoutapparatus means for successively reading out each second group of storedsignals, and

second summing means for summing the stored first output signals of eachsecond group read out from said second storage means to provide at saidsecond output means a second output signal proportional in apredetermined manner to the first output signals of the particularsecond group being summed, said second output signals of said secondmeans being sequentially provided thereby at a second output rate lessthan said input rate; and

control means for providing control'signals for actuating said first andsecond write apparatus means and said first and second readout apparatusmeans in a predetermined relationship, said second write means beingactuated each time said first readout means is actuated.

2. A data compaction system according to claim 1 wherein said first andsecond storage means are comprised as an integral member.

3. A data compaction system according to claim 2 wherein said integralstorage member is of the magnetic storage drum type.

4. A data compaction system according to claim 1 further comprisingmeans for adjusting the respective levels of the data signals of eachfirst group in proportion to a predetermined reference function prior tothe summation thereof in said first summing means.

5. A data compaction system according to claim 1 further comprisingmeans for adjusting the respective levels of the first output signals ofeach second group in proportion to a predetermined reference functionprior to the summation thereof in said second summing means.

6. A data compaction system according to claim 1 further comprisingfirst adjusting means for adjusting the respective levels of the datasignals of each first group in proportion to a predetermined firstreference function prior to the summation thereof in said first summingmeans, and second adjusting means for adjusting the respective levels ofthe first output signals of each second group in proportion to apredetermined second reference function prior to the summation thereofin said second summing means.

7. A data processing system comprising:

a signal source for providing data signals at a predetermined firstrate;

a data compactor having presumming means and correlation means,

said presumming means having first output means and including firststoring means and first write apparatus means for storing said inputdata signals in successive first groups in said first storage means,each of said first groups containing a plural first number of successivedata signals, first readout apparatus means for successively reading outin a parallel mode each first group of stored signals, and

first summing means for summing the stored data signals of each firstgroup read out from said first storage means to provide at said firstoutput means a first output signal proportional in a predeterminedmanner to the data signals of the particular first group being summed,said first output signals of said first summing means being sequentiallyprovided thereby at a second rate less than said first rate, and saidcorrelator means having second output means, and including secondstorage means and second write apparatus means for storing said firstoutput signals in successive second groups in said second storage means,each of said second groups containing a plural second number ofsuccessive first out-output signals, second readout apparatus means forsuccessively reading out each second group of stored signals, and

second summing means for summing the stored first output signals of eachsecond group read out from said second storage means to provide at saidsecond output means a second output signal proportional in apredetermined manner to the first output signals of the particularsecond group being summed, said second output signals of said secondmeans being sequentially provided thereby at a third rate less than saidfirst rate; utilization means responsive to said second output signals;and

control means for providing control signals for actuating said first andsecond write apparatus means and said first and second readout apparatusmeans in a predetermined relationship, said second write means beingactuated each time said first readout means is actuated.

8. A data processing system according to claim 7 wherein said first andsecond storage means are comprised as an integral member. 1

9. A data processing system according to claim 8 wherein said integralstorage member is of the magnetic storage drum type.

10. A data processing system according to claim 7 further comprisingmeans for adjusting the respective levels of the data signals of eachfirst group in proportion to a predetermined reference function prior tothe summation thereof in said first summing means.

11. A data processing system according to claim 7 further comprisingmeans for adjusting the respective levels of the first output signals ofeach second group in proportion to a predetermined reference functionprior to the summation thereof in said second summing means.

12. A data processing system according to claim 7 further comprisingfirst adjusting means for adjusting the respective levels of the datasignals of each first group in proportion to a predetermined firstreference function prior to the summation thereof in said first summingmeans, and second adjusting means for adjusting the respective levels ofthe first output signals of each second group in proportion to apredetermined second reference function prior to the summation thereofin said second summing means.

13. A radar data processing system comprising;

a radar data signal source for providing radar data signals at apredetermined first rate, each of said data signals having predeterminedranges and azimuth information;

a data compactor having presumming means and correlator means, saidpresumming means having first output means and including 5 first storagemeans and first write apparatus means for storing said input datasignals in successive first groups in said first storage means, each ofsaid first groups containing a plural first number of successive datasignals, first readout apparatus means for successively reading out in aparallel mode each first group of stored signals, and first summingmeans for summing the stored data signals of each first group read outfrom said first storage means to provide at said first output means afirst out put signal proportional in a predetermined manner to the datasignals of the particular first group being summed, said first outputsignals of said first summing means being sequentially provided therebyat a second 2 rate less than said first rate, and

said correlator means having second output means, and including secondstorage means and second write apparatus means for storing said firstoutput signals in successive second groups in said second storage means,each of said second groups containing a plural second number ofsuccessive first output signals, and

second summing means for summing the stored first output signals of eachsecond group read out from said second storage means to provide at saidsecond output means a second output signal proportional in apredetermined manner to the first output signals of the particularsecond group being summed, said second output signals of said secondmeans being sequentially provided thereby at a third output rate lessthan said first rate;

utilization means responsive to said second output signals;

and

control means for providing control signals for actuating 40 said firstand second write apparatus means and said first and second readoutapparatus means in a predetermined relationship, said second write meansbeing actuated each time said first readout means is actuated.

14. Aradar data processing system according to claim 13 wherein saidfirst and second storage means are comprised as an integral member.

15. A radar data processing system according to claim 14 wherein saidintegral storage member is of the magnetic storage drurn type.

16. A radar data processing system according to claim 13 furthercomprising means for adjusting the respective levels of the data signalsof each first group in proportion to a predetermined reference functionprior to the summation thereof in said first summing means.

17. A radar data processing system according to claim 13 furthercomprising means for adjusting the respective levels of the first outputsignals of each second group in proportion to a predetermined referencefunction prior to the summation thereof in said second summing means.

18. A radar data processing system according to claim 13 furthercomprising first adjusting means for adjusting the respective levels ofthe data signals of each first group in proportion to a predeterminedfirst reference function prior to the summation thereof in said firstsumming means, and second adjusting means for adjusting the respectivelevels of the first output signals of each second group in proportion toa predetermined second reference function prior to the summation thereofin said second summing means.

19. A radar data processing system according to claim 13 wherein saidsource of plural radar signals further comprises:

a radar transmitter and receiver therefor of a predetermined radar type.

20. A radar data processing system according to claim 19 wherein saidradar type is a side-looking pulsed radar system.

21. A radar data compaction system for compacting sequential pluralradar data signals being applied thereto at a predetermined input rate,each of said radar data signals having predetermined range and azimuthinformation characteristics, said system comprising:

presumming means having first output means, said presumming includingfirst storage means and first write apparatus means for storing saidinput data signals in successive first groups in said first storagemeans, number of said first groups containing a plural first number ofsuccessive data signals, first readout apparatus means for successivelyreading out in a parallel mode each each group of stored signals, and

first summing means for summing the stored data signals of each firstgroup read out from said first storage means to provide at said firstoutput means a first output signal proportional in a predeterminedmanner to the data signals of the particular first group being summed,said first output signals of said first summing means being sequentiallyprovided thereby at a first output rate less than said input rate;

correlator means having second output means, said correlator meansincluding second storage means and second write apparatus means forstoring said first output signals in successive second groups, each ofsaid second groups containing a plural second number of successive firstoutput signals, and

second summing means for summing the stored first output signals of eachsecond group read out from said second storage means to provide at saidsecond output means a second output signal proportional in apredetermined manner to the first output signals of the particularsecond group being summed, said second s output signals of said secondmeans being sequentially provided thereby at a second output rate lessthan said input rate; and

control means for providing control signals for actuating said first andsecond write apparatus means and said first and second readout apparatusmeans in a predetermined relationship, said second write means beingactuated each time said first readout means is actuated.

22. A radar data compaction system according to claim 21 wherein saidfirst and second storage means are comprised as an integral member.

23. A radar data compaction system according to claim 22 wherein saidintegral storage member is of the magnetic storage drum type.

24. A radar data compaction system according to claim 21 furthercomprising means for adjusting the respective levels of the data signalsof each first group in proportion to a predetermined reference functionprior to the summation thereof in said first summing means.

25. A radar data compaction system according to claim 21 furthercomprising means for adjusting the respective levels of the first outputsignals of each second group in proportion to a predetermined referencefunction prior to the summation thereof in said second summing means.

26. A radar data compaction system according to claim 21 furthercomprising first adjusting means for adjusting the respective levels ofthe data signals of each first group in proportion to a predeterminedfirst reference function prior to the summation thereof in said firstsumming means, and second adjusting means for adjusting the respectivelevels of the first output signals of each second group in proportion toa predetermined second reference function prior to the summation thereofin said second summing means.

1. A data compaction system for compacting sequential input data signalsbeing applied thereto at a predetermined input rate, said systemcomprising: presumming means having first output means, said presummingmeans including first storage means and first write apparatus means forstoring said input data signals in successive first groups in said firststorage means, each of said first groups containing a plural firstnumber of successive data signals, first readout apparatus means forsuccessively reading out in a parallel mode each first group of storedsignals, and first summing means for summing the stored data signals ofeach first group read out from said first storage means to provide atsaid first output means a first output signal proportional in apredetermined manner to the data signals of the particular first groupbeing summed, said first output signals of said first summing meansbeing sequentially provided thereby at a first output rate less thansaid input rate; correlator means having second output means, saidcorrelator means inCluding second storage means and second writeapparatus means for storing said first output signals in successivesecond groups in said second storage means, each of said second groupscontaining a plural second number of successive first output signals,second readout apparatus means for successively reading out each secondgroup of stored signals, and second summing means for summing the storedfirst output signals of each second group read out from said secondstorage means to provide at said second output means a second outputsignal proportional in a predetermined manner to the first outputsignals of the particular second group being summed, said second outputsignals of said second means being sequentially provided thereby at asecond output rate less than said input rate; and control means forproviding control signals for actuating said first and second writeapparatus means and said first and second readout apparatus means in apredetermined relationship, said second write means being actuated eachtime said first readout means is actuated.
 2. A data compaction systemaccording to claim 1 wherein said first and second storage means arecomprised as an integral member.
 3. A data compaction system accordingto claim 2 wherein said integral storage member is of the magneticstorage drum type.
 4. A data compaction system according to claim 1further comprising means for adjusting the respective levels of the datasignals of each first group in proportion to a predetermined referencefunction prior to the summation thereof in said first summing means. 5.A data compaction system according to claim 1 further comprising meansfor adjusting the respective levels of the first output signals of eachsecond group in proportion to a predetermined reference function priorto the summation thereof in said second summing means.
 6. A datacompaction system according to claim 1 further comprising firstadjusting means for adjusting the respective levels of the data signalsof each first group in proportion to a predetermined first referencefunction prior to the summation thereof in said first summing means, andsecond adjusting means for adjusting the respective levels of the firstoutput signals of each second group in proportion to a predeterminedsecond reference function prior to the summation thereof in said secondsumming means.
 7. A data processing system comprising: a signal sourcefor providing data signals at a predetermined first rate; a datacompactor having presumming means and correlation means, said presummingmeans having first output means and including first storing means andfirst write apparatus means for storing said input data signals insuccessive first groups in said first storage means, each of said firstgroups containing a plural first number of successive data signals,first readout apparatus means for successively reading out in a parallelmode each first group of stored signals, and first summing means forsumming the stored data signals of each first group read out from saidfirst storage means to provide at said first output means a first outputsignal proportional in a predetermined manner to the data signals of theparticular first group being summed, said first output signals of saidfirst summing means being sequentially provided thereby at a second rateless than said first rate, and said correlator means having secondoutput means, and including second storage means and second writeapparatus means for storing said first output signals in successivesecond groups in said second storage means, each of said second groupscontaining a plural second number of successive first out outputsignals, second readout apparatus means for successively reading outeach second group of stored signals, and second summing means forsumming the stored first output signals of each second group read outfrom said second storage means to provide at said second output mEans asecond output signal proportional in a predetermined manner to the firstoutput signals of the particular second group being summed, said secondoutput signals of said second means being sequentially provided therebyat a third rate less than said first rate; utilization means responsiveto said second output signals; and control means for providing controlsignals for actuating said first and second write apparatus means andsaid first and second readout apparatus means in a predeterminedrelationship, said second write means being actuated each time saidfirst readout means is actuated.
 8. A data processing system accordingto claim 7 wherein said first and second storage means are comprised asan integral member.
 9. A data processing system according to claim 8wherein said integral storage member is of the magnetic storage drumtype.
 10. A data processing system according to claim 7 furthercomprising means for adjusting the respective levels of the data signalsof each first group in proportion to a predetermined reference functionprior to the summation thereof in said first summing means.
 11. A dataprocessing system according to claim 7 further comprising means foradjusting the respective levels of the first output signals of eachsecond group in proportion to a predetermined reference function priorto the summation thereof in said second summing means.
 12. A dataprocessing system according to claim 7 further comprising firstadjusting means for adjusting the respective levels of the data signalsof each first group in proportion to a predetermined first referencefunction prior to the summation thereof in said first summing means, andsecond adjusting means for adjusting the respective levels of the firstoutput signals of each second group in proportion to a predeterminedsecond reference function prior to the summation thereof in said secondsumming means.
 13. A radar data processing system comprising; a radardata signal source for providing radar data signals at a predeterminedfirst rate, each of said data signals having predetermined ranges andazimuth information; a data compactor having presumming means andcorrelator means, said presumming means having first output means andincluding first storage means and first write apparatus means forstoring said input data signals in successive first groups in said firststorage means, each of said first groups containing a plural firstnumber of successive data signals, first readout apparatus means forsuccessively reading out in a parallel mode each first group of storedsignals, and first summing means for summing the stored data signals ofeach first group read out from said first storage means to provide atsaid first output means a first output signal proportional in apredetermined manner to the data signals of the particular first groupbeing summed, said first output signals of said first summing meansbeing sequentially provided thereby at a second rate less than saidfirst rate, and said correlator means having second output means, andincluding second storage means and second write apparatus means forstoring said first output signals in successive second groups in saidsecond storage means, each of said second groups containing a pluralsecond number of successive first output signals, and second summingmeans for summing the stored first output signals of each second groupread out from said second storage means to provide at said second outputmeans a second output signal proportional in a predetermined manner tothe first output signals of the particular second group being summed,said second output signals of said second means being sequentiallyprovided thereby at a third output rate less than said first rate;utilization means responsive to said second output signals; and controlmeans for providing control signals for actuating said first and secondwrite apparatus means and said first and secoNd readout apparatus meansin a predetermined relationship, said second write means being actuatedeach time said first readout means is actuated.
 14. A radar dataprocessing system according to claim 13 wherein said first and secondstorage means are comprised as an integral member.
 15. A radar dataprocessing system according to claim 14 wherein said integral storagemember is of the magnetic storage drum type.
 16. A radar data processingsystem according to claim 13 further comprising means for adjusting therespective levels of the data signals of each first group in proportionto a predetermined reference function prior to the summation thereof insaid first summing means.
 17. A radar data processing system accordingto claim 13 further comprising means for adjusting the respective levelsof the first output signals of each second group in proportion to apredetermined reference function prior to the summation thereof in saidsecond summing means.
 18. A radar data processing system according toclaim 13 further comprising first adjusting means for adjusting therespective levels of the data signals of each first group in proportionto a predetermined first reference function prior to the summationthereof in said first summing means, and second adjusting means foradjusting the respective levels of the first output signals of eachsecond group in proportion to a predetermined second reference functionprior to the summation thereof in said second summing means.
 19. A radardata processing system according to claim 13 wherein said source ofplural radar signals further comprises: a radar transmitter and receivertherefor of a predetermined radar type.
 20. A radar data processingsystem according to claim 19 wherein said radar type is a side-lookingpulsed radar system.
 21. A radar data compaction system for compactingsequential plural radar data signals being applied thereto at apredetermined input rate, each of said radar data signals havingpredetermined range and azimuth information characteristics, said systemcomprising: presumming means having first output means, said presummingincluding first storage means and first write apparatus means forstoring said input data signals in successive first groups in said firststorage means, number of said first groups containing a plural firstnumber of successive data signals, first readout apparatus means forsuccessively reading out in a parallel mode each each group of storedsignals, and first summing means for summing the stored data signals ofeach first group read out from said first storage means to provide atsaid first output means a first output signal proportional in apredetermined manner to the data signals of the particular first groupbeing summed, said first output signals of said first summing meansbeing sequentially provided thereby at a first output rate less thansaid input rate; correlator means having second output means, saidcorrelator means including second storage means and second writeapparatus means for storing said first output signals in successivesecond groups, each of said second groups containing a plural secondnumber of successive first output signals, and second summing means forsumming the stored first output signals of each second group read outfrom said second storage means to provide at said second output means asecond output signal proportional in a predetermined manner to the firstoutput signals of the particular second group being summed, said secondoutput signals of said second means being sequentially provided therebyat a second output rate less than said input rate; and control means forproviding control signals for actuating said first and second writeapparatus means and said first and second readout apparatus means in apredetermined relationship, said second write means being actuated eachtime said first readout means is actuated.
 22. A radAr data compactionsystem according to claim 21 wherein said first and second storage meansare comprised as an integral member.
 23. A radar data compaction systemaccording to claim 22 wherein said integral storage member is of themagnetic storage drum type.
 24. A radar data compaction system accordingto claim 21 further comprising means for adjusting the respective levelsof the data signals of each first group in proportion to a predeterminedreference function prior to the summation thereof in said first summingmeans.
 25. A radar data compaction system according to claim 21 furthercomprising means for adjusting the respective levels of the first outputsignals of each second group in proportion to a predetermined referencefunction prior to the summation thereof in said second summing means.26. A radar data compaction system according to claim 21 furthercomprising first adjusting means for adjusting the respective levels ofthe data signals of each first group in proportion to a predeterminedfirst reference function prior to the summation thereof in said firstsumming means, and second adjusting means for adjusting the respectivelevels of the first output signals of each second group in proportion toa predetermined second reference function prior to the summation thereofin said second summing means.